I used this plugin mounted to the side of the bumper instead so that crap couldn't accumulate in it if the cover popped up. Then I used a triple tap cord, cutting one end off and wiring it directly to the plug. The triple tap is secured up under the hood with the block heater and this battery charger plugged into it. In the summer, since my truck sits for long periods of time, I just unplug the block heater from the triple tap and plug the truck in normally to keep the batteries topped up.